U.S. patent number 5,643,392 [Application Number 08/358,343] was granted by the patent office on 1997-07-01 for method of and apparatus for delaminating imaging media.
This patent grant is currently assigned to Polaroid Corporation. Invention is credited to Arthur H. Clough.
United States Patent |
5,643,392 |
Clough |
July 1, 1997 |
Method of and apparatus for delaminating imaging media
Abstract
A method and apparatus are provided which act to peel different
types of dry laminar imaging media having different peel
attributes.
Inventors: |
Clough; Arthur H. (Hardwick,
MA) |
Assignee: |
Polaroid Corporation
(Cambridge, MA)
|
Family
ID: |
23409288 |
Appl.
No.: |
08/358,343 |
Filed: |
December 19, 1994 |
Current U.S.
Class: |
156/715; 156/760;
271/280; 271/285; 396/661; 430/256 |
Current CPC
Class: |
B29C
63/0013 (20130101); G03F 7/34 (20130101); Y10T
156/1174 (20150115); Y10T 156/1956 (20150115) |
Current International
Class: |
B29C
63/00 (20060101); G03F 7/34 (20060101); B32B
035/00 () |
Field of
Search: |
;156/344,584
;271/280,281,285 ;430/256,257,258,259,260,261 ;354/354 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
5366582 |
November 1994 |
Freeman et al. |
5478434 |
December 1995 |
Kerr et al. |
|
Primary Examiner: Osele; Mark A.
Attorney, Agent or Firm: Payne; Leslie
Claims
What is claimed is:
1. An apparatus for delaminating layers of a laminated sheet of
imaging medium, wherein the laminated sheet includes an image
substrate, an intermediate image forming layer, and an overlying
peelable layer, the substrate layer being provided with a frangible
tab portion located between a score line in a free surface of the
substrate and an adjacent marginal edge of the medium; said
apparatus comprising:
a frame assembly, peeling means operatively associated with said
frame assembly at said peeling station and being operative for
peeling at least a peelable layer of at least one sheet of an
imaging medium from a substrate of the imaging medium at a peeling
station, wherein said peeling means is adjustable for peeling
different sheets of an imaging medium having different
predetermined peeling characteristics; wherein said peeling means
includes a first peeling means for peeling the peelable layer from
a sheet medium having a first set of peeling characteristics; a
second peeling means for peeling the peelable layer from a sheet
medium having a second set of peeling characteristics; and, means
for presenting either of said first or second peeling means to the
advancing sheet at said peeling station so as to effect peeling of
a corresponding one of the sheet media having the first or second
peeling characteristics; respectively, and said presenting means
being operable for peeling the peelable layer from the substrate as
the sheet medium is advanced therepast.
2. An apparatus for delaminating layers of a laminated sheet of
imaging medium, wherein the laminated sheet includes an image
substrate layer, an intermediate image forming layer, and an
overlying peelable throwaway layer, the substrate being provided
with a frangible tab portion located between a score line in a free
surface of the substrate and an adjacent marginal edge of the
medium; said apparatus comprising: a frame assembly; peeling means
operatively associated with said frame assembly at a peeling
station and being operative for peeling at least a peelable layer
of the imaging medium from a substrate of the imaging medium at
said peeling station, wherein said peeling means is adjustable for
peeling different sheets of an imaging medium having different
predetermined peeling characteristics; wherein said peeling means
includes at least a first and a second peeling bar assembly,
wherein said second peeling bar assembly is movable relative to
said first peeling bar assembly, each of said first and second
peeling bar assemblies includes a respective first and second
peeling edge; wherein each of said peeling edges is adapted to be
at a peeling position at said peeling station, and each of said
peeling edges is configured to peel sheets of imaging media having
respectively different peeling characteristics; wherein said
peeling means includes means for moving said second peeling bar
assembly such that said second peeling edge is at said peeling
position; said first peeling bar assembly being stationarily
positioned at said peeling station so that said first peeling edge
is located at said peeling position; wherein said first peeling bar
assembly includes an elongated bar which extends across a path of
sheet travel through said peeling means; said second peeling bar
assembly is an elongated member having a longitudinally extending
cavity which at least partially receives therein said bar of said
first peeling bar assembly, and which permits movement of said
first peeling bar assembly relative to said second peeling bar
assembly.
3. The apparatus of claim 2 wherein said first peeling bar assembly
includes peel surface means upon which the peelable layer is
supported as it is being peeled from the substrate layer.
4. The apparatus of claim 3 wherein said peel surface means is
operative for supporting the peelable layer when said second
peeling edge is at said peeling position.
5. The apparatus of claim 4 wherein said peel surface means is an
arcuate peeling surface.
6. The apparatus of claim 3 wherein said peeling means further
includes:
traction roller means including a traction peel roller assembly
which is mounted for movement between a medium non-engaging
position and a medium engaging position, wherein whenever said
traction peel roller assembly is in said engaging position the
peelable layer is engaged thereby for urging and advancing the
peelable layer against said peel surface means for effecting
peeling.
7. The apparatus of claim 6 wherein whenever said traction peel
roller assembly is in said non-engaging position it is positioned
below both of said first and second peeling edges; and whenever
said traction peel roller assembly moves from said non-engaging
position to said engaging position, said traction peel roller means
moves upwardly and engages and wraps the tab about at least one or
both of said first and second peel edges.
8. The apparatus of claim 7 wherein said peel traction roller means
includes a drive assembly which moves said traction peel roller
assembly in an arc between said non-engaging position and said
engaging position.
9. The apparatus of claim 8 wherein traction peel roller assembly
includes a peel shaft which is rotatably driven at preselected
speeds, and said drive assembly includes a pinion gear coupled to
one end of said peel shaft, and a rotatably driven ring-gear means
having an internal tooth assembly which meshes with said pinion
gear for rotating said peel shaft and thereby said traction peel
roller assembly in response to rotation of said ring-gear
means.
10. The apparatus of claim 9 wherein said drive assembly includes a
crankplate means mounted to said frame assembly for rotatably
mounting said peel shaft for rotation about its longitudinal axis
and for movement of said traction peel roller assembly in said arc
between said non-engaging and engaging positions.
11. The apparatus of claim 10 wherein said traction peel roller
assembly includes a plurality of axially spaced apart drive
elements mounted on said peel shaft; said drive elements being made
of a compliant elastomeric material which is radially compressible
so as to compensate for deviations in the position of said slip
surface means, and which has sufficient friction for peeling of the
peelable layer.
12. The apparatus of claim 11 wherein said compliant material is
made of a group of materials which includes polyurethane, natural
and synthetic rubbers.
13. The apparatus of claim 12 wherein said drive elements are rings
and have voids formed therein, wherein said voids are formed to
enhance the radial compressibility and torsional stiffness of said
drive elements.
14. The apparatus of claim 13 further including deflecting means
coupled to said frame assembly adjacent said peeling station and
being movable to an operative position for deflecting the substrate
layer at a location downstream of said traction peel roller
assembly by an amount so as to facilitate peeling of the substrate
layer as the peelable layer is being peeled by said traction roller
means.
15. The apparatus of claim 14 wherein said deflecting means is
movable between said operative an inoperative position, and is
biased relative to said peel traction means so as to be movable in
response to movement of said traction peel roller assembly between
said engaging and non-engaging positions; respectively.
16. The apparatus of claim 15 wherein said deflecting means is
pivotal about a pivoting axis and includes a deflecting roller,
said deflecting roller is movable to a plurality of positions,
wherein each of said deflecting roller positions has a different
radius relative to said pivoting axis, such that when said
deflecting roller is at each of said positions it is responsible
for deflecting a peeled substrate sheet at a different angle so as
to enhance peeling sheets of imaging medium having different peel
characteristics.
17. The apparatus of claim 14 further including advancing means
operatively associated with said frame assembly for advancing a
sheet of imaging medium along a path to said peeling station.
18. The apparatus of claim 17 wherein said advancing means includes
tension roller means mounted on said frame assembly and being
operative to move between first and second positions, wherein when
in said first position said tension roller means is active for
squeezing at least one imaging sheet against a surface of said
peeling means so as to create tension on the advancing sheet,
whereby said tension roller means effects passive tensioning of the
sheet regardless of width and without the need of positively
driving the sheet to said peeling position; said tension roller
means also being operative to advance a plurality of advancing
sheets at the same time and in side-by-side relationship.
19. The apparatus of claim 18 wherein said tension roller means is
biased towards said first position and into effective operative
relationship with said traction peel roller assembly, such that as
said peel roller assembly moves from said non-engaging position to
said engaging position said tension roller means moves from said
second position to said first position.
20. The apparatus of claim 19 wherein said tension roller means
includes a plurality of independently biased rollers, each of which
acts independently on an advancing sheet so as to induce drag for
creating tension for optimal peeling of the sheet, whereby a
plurality of separate sheets can be advanced in side-by-side
relationship to said peeling position.
21. The apparatus of claim 20 wherein said roller means is made of
a resiliently flexible material which is sized so as to passively
engage advancing sheets and squeeze the sheets against a surface of
said peeling means.
22. The apparatus of claim 18 wherein said peel traction roll
assembly includes means for moving both said deflection roller
assembly and said tension roller assembly out of engagement with
said traction peel roller assembly when said traction roller means
is in its inoperative position.
23. A process of delaminating layers of a laminated sheet of an
imaging medium, wherein the laminated sheet includes an image
substrate layer, an intermediate image forming layer, and an
overlying peelable throwaway layer, the substrate layer being
provided with a frangible tab portion located between a score line
in a free surface of the substrate and an adjacent marginal edge of
the media; said process comprising the steps of:
advancing a sheet of imaging medium along a path to a peeling
station;
providing a first peeling means which can peel the peelable layer
from a sheet medium having a first set of peeling
characteristics;
providing a second peeling means which can peel the peelable layer
from a sheet medium having a second set of peeling
characteristics;
presenting either of the first or second peeling means to the
advancing sheet at said peeling station so as to effect peeling of
a corresponding one of the sheet media having the first or second
peeling characteristics; respectively, and,
peeling the peelable layer from the substrate as the sheet medium
is advanced past the peeling station.
24. The process of claim 23 further including the step of moving at
least one of the first and second peeling means relative to the
other so as to present itself at the peeling station for effecting
peeling.
25. The process of claim 24 wherein the peelable layer is supported
along and by a peel slip surface as it is being peeled from the
substrate layer which peel slip surface is usable with both the
first and second peel means.
26. The process of claim 25 wherein said peeling step includes
providing a peel traction roller means comprising a peel traction
roller assembly which is mounted for movement between a sheet
medium non-engaging position and a sheet medium engaging position,
whereby whenever the peel traction roller means moves between its
operative and inoperative positions; respectively, the traction
peel roller assembly is in the engaging position and the peelable
layer is engaged for urging and advancing the peelable layer
against the peel slip surface for effecting peeling.
27. The process of claim 26 wherein said peeling step includes
having the traction peel roller assembly moved to its non-engaging
position below both of first and second peeling edges of the first
and second peeling means; respectively, and moving the traction
peel roller assembly from its non-engaging position to its engaging
position so that it moves upwardly and engages and wraps the tab
portion of a sheet medium about at least one or both of first and
second peel edges.
28. The process of claim 27 wherein the traction peel roller
assembly is rotated at different preselected speeds for the
different sheet media having the different peeling
characteristics.
29. The process of claim 28 wherein the step of providing the
traction peel roller assembly includes the step of providing a
plurality of axially spaced apart drive elements mounted on a peel
shaft, wherein the drive elements are made of a compliant
elastomeric material which is radially compressible so as to
compensate for deviations in the position of the peel surface and
which has sufficient friction for uniform peeling of the peelable
layer.
30. The process of claim 29 wherein the compliant material provided
is made of a group of materials which includes polyurethane,
natural and synthetic.
31. The process of claim 30 wherein the drive elements provided are
rings with voids formed therein to enhance the radial
compressibility and torsional stiffness of the rings.
32. The process of claim 29 further including the step of
deflecting the substrate layer adjacent the peeling station, at a
location downstream of the peeling station, as the sheet medium is
being peeled by the traction peel roller means so as to facilitate
peeling of the substrate layer.
33. The process of claim 32 wherein said deflecting step includes
the step of deflecting the substrate layer by different amounts
depending on the peeling characteristics of the media being peeled,
wherein said step of deflecting by different amounts includes use
of a deflection roller which is movable to at least two distinct
positions when in an operative position.
34. The process of claim 33 wherein the deflecting means is movable
between its operative and inoperative positions and is biased
relative against the peel traction means so as to be movable in
response to movement of the peel traction roller means between the
engaging and non-engaging positions; respectively.
35. The process of claim 34 wherein said step of advancing the
sheet medium includes the step of providing tension roller means
which includes a plurality of individual tension rollers being
operative to move between first and second positions, wherein when
the rollers are in the first position the tension rollers are
biased for active squeezing of at least one imaging sheet medium
against a surface of at least one of the first or second peel means
so as to create tension on the advancing sheet medium, whereby the
tension roller means effects passive tensioning of the sheet
regardless of width and without the need of positively driving the
sheet to said peeling station; the tension roller means also being
operative to tension a plurality of advancing sheets at the same
time and in side-by-side relationship.
36. The process of claim 35 wherein said step of providing the
tension rollers includes biasing the rollers to the first position
and into effective operative relationship with the peel traction
roller assembly, such that as the peel traction roller assembly
moves from the non-engaging position to the engaging position, the
rollers move from the second position to the first position.
37. The process of claim 36 wherein the step of providing the
tension rollers includes providing rollers which act independently
to bias the advancing sheet for inducing drag on the sheet
sufficient for creating the tension for assisting in the optimal
peeling of the sheet.
38. The process of claim 37 wherein the step of providing rollers
includes providing rollers which are resiliently flexible and are
sized so as to engage the advancing sheets and squeeze them against
a surface of one of the first or second peeling means.
39. The process of claim 38 further including the step of
maintaining the tension rollers and the deflecting roller out of
engagement with the traction peel roller assembly when the latter
is in its inoperative condition.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention is related to commonly assigned and copending
U.S. patent application Ser. No. 08/343,224, entitled "MEDIA
TABBING APPARATUS AND METHOD"; filed on Nov. 22, 1994.
BACKGROUND OF THE INVENTION
The present invention relates generally to apparatus and methods
for delaminating or peeling thin laminated sheets of material and,
in particular, to a method of and apparatus for adjustably
delaminating sheets of dry laminar imaging media having different
peeling characteristics.
Prior systems are known for processing sheets of dry laminar
imaging media by delaminating or peeling certain layers therefrom
following the formation of images thereon. One such approach is
described in commonly assigned U.S. Pat. No. 5,159,352, wherein
images are formed on a thermographic type of dry laminar imaging
media by the selective application of heat to discrete areas of the
medium. In this regard, one sheet of the medium of the
thermographic medium comprises a substrate or "keeper" layer or
sheet, an overlying peel sheet or "throwaway" layer adhesively
connected by an intermediate multicomponent image forming layer
which may include pigment material and a binder therefor. In the
laminar composite sheet structure the adhesive bond between the
substrate sheet and the image forming layer is, in its initial
unexposed state, greater than the bond strength between the peel
sheet and the image forming layer. As a result of exposure to
thermal energy applied by lasers, the bond between the exposed
portions of the image forming layer and the peel sheet becomes
stronger than the bond existing between the substrate and the image
forming layer. Portions of the image forming layer which have been
exposed can be separated from portions which have not been exposed
by delaminating the peel sheet from the substrate; whereby
complementary images are formed on the respective peel sheet and
substrate. Peeling layers from a thin laminate such as described
above is, however, an extremely delicate process because
commercially objectionable image artifacts can be introduced into
the final images if the adjacent exposed and unexposed portions are
not peeled in the intended manner.
The sheet delamination apparatus of the invention can be employed
for the processing of various types of dry laminar imaging media,
including those which provide images by resorting to different
imaging mechanisms than heat. Such media forms the complementary
images thereon by the selective application of different sources of
energy. In the field of graphics arts imaging, there is a need for
one imaging medium designed for the production of a duplicate of an
original (i.e., a right-reading positive image, referred to as a
"dupe" image) and another imaging medium for the production of a
right-reading negative image of the original (referred to as a
"contact" image). It will be appreciated that laminar imaging media
of "dupe" and "contact" types will be based upon different chemical
formulation and will provide their respective images by the
operation of different imaging mechanisms. Accordingly, the forces
required for separating the respective layers will differ in a
predetermined manner.
It is, therefore, highly desirable to be able to use the same
apparatus for optimally peeling different imaging types of imaging
media having respectively different peeling characteristics.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a
method of and apparatus for delaminating sheets of peel-apart dry
laminated imaging media. Included in an apparatus which embraces
the invention is a frame assembly, and a delaminating means. The
delaminating means is associated with the frame assembly and is
operative for delaminating sheets of media which are fed along a
path to a delaminating station. Provision is made for a
delaminating means operatively associated with the frame assembly
and being operative for delaminating a peelable layer from a
remaining keeper layer of the dry imaging medium. The delaminating
means of this invention is adjustable for delaminating sheets of
imaging medium having respectively different predetermined peeling
attributes.
In one illustrated embodiment, the delaminating means is adjustable
and includes a main peeling assembly, and an auxiliary peeling
assembly. The main peeling assembly is stationed to engage a sheet
of one kind of dry peel apart imagine medium which advances
therepast so as to effect a peeling between keeper and throwaway
layers. The auxiliary peeling assembly is movable into and out of
operative relationship with the main peeling assembly. When it is
in the operative position, the auxiliary peeling assembly
facilitates peeling of an imaging sheet medium having different
peeling attributes than the kind peeled by the main peeling
assembly. When the auxiliary peeling assembly is moved to its
inoperative position, it allows the main peeling assembly to be
operative for peeling the first kind of medium.
In an illustrated embodiment, the delaminating means comprises a
traction roller assembly which includes a traction peel roller
mounted for movement between a sheet medium non-engaging position,
and a sheet medium engaging position. Whenever, the traction peel
roller is in the engaging position, the traction peel roller
engages a throwaway layer of the laminated sheet medium for urging
and advancing the throwaway layer portion against a slip surface
for effecting peeling.
In another embodiment the traction roller assembly further includes
a deflecting device which is coupled to the frame assembly adjacent
the peeling station. The deflecting device includes a roller which
is movable to an operative position for deflecting the keeper layer
sheet at a location downstream of the traction peel roller as the
throwaway sheet is being peeled by the traction roller assembly so
as to facilitate peeling action.
In another illustrated embodiment, there is provided an adjustable
peeling assembly which includes at least first and second peeling
assemblies. These peeling assemblies are positionable at the
peeling station and extend across a path of the advancing dry peel
apart imaging medium. Each one of the first and second peeling
assemblies has a peeling edge surface which is configured to peel
media having different predetermined peeling characteristics;
respectively.
In another illustrated embodiment, the first peeling assembly is
stationarily located at the peeling station, and the second peeling
assembly is movable between a non-peeling position and a peeling
position relative to the first peeling assembly. The peeling
surface of the second peeling assembly is in a nested relationship
to the peeling surface of the first peeling assembly when the
second peeling assembly is in the peeling position, such that the
second peeling surface is located to engage the leading edge of an
imaging sheet advancing toward it.
In another illustrated embodiment, there is provided an advancing
means which includes a tensioning roller assembly for squeezing
each medium sheet against one of the first and second peeling
assemblies so as to create tension on the advancing sheet, whereby
the tensioning roller assembly effects passive advancement of
sheets, such that sheets of varying widths and at different
locations can be advanced to the peeling station so as to be
peeled.
In an illustrated embodiment, the tensioning roller assembly
includes a plurality of axially spaced apart elastomeric rollers,
each of which acts as a spring independently of the others on the
sheet for inducing drag on the sheet and for thereby creating the
tension.
In an illustrated embodiment the film advances at preselected
speeds dependent on the medium being peeled so as to effect a
peeling which is free of imaging artifacts.
In another illustrated embodiment, the first peeling assembly
includes a main peeling bar which has an arcuate peeling surface
thereon that acts to peel the throwaway sheet and also guides a
sheet exiting therefrom into a waste conveying system.
In another illustrated embodiment, the second peeling assembly
includes an auxiliary peeling bar assembly which has a peeling
profile which is configured so as to peel the imaging media without
inducing imaging artifacts.
In an illustrated embodiment, the auxiliary peel bar assembly is
advanced between an operative peeling position and an inoperative
non-peeling position, whereby the auxiliary peeling bar assembly
can peel sheets having different peeling characteristics than the
sheets peeled with the main peeling bar assembly.
In an illustrated embodiment, there is provided a deflector roller
assembly which is adjustable so as to be operative in at least two
conditions, wherein in either one of the two conditions a keeper
sheet of the dry imaging medium is deflected by a predetermined
amount so as to enhance delamination in a manner which does not
form image artifacts.
Among the other objects and features of the present invention, are,
therefore, the provisions of: peeling method and apparatus which
are adapted for peeling different media having different peeling
characteristics; peeling method and apparatus which are adapted for
handling different sized sheets simultaneously; peeling method and
apparatus which simply and reliably effects peeling of laminated
imaging media; peeling method and apparatus which reduces
significantly imaging artifacts in the peeled image so that there
is virtually no distortion of the image; and peeling method and
apparatus which is inexpensive to both manufacture and operate.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawings in which there is
shown an illustrative preferred embodiment of the invention,
wherein:
FIG. 1 is an elevational schematic view showing a self-contained
peeler and laminator apparatus for the processing of thin laminated
sheets of a dry laminar imaging medium which apparatus includes the
peeling apparatus of the present invention;
FIG. 1A is an elevational view of a peeler in-feed mechanism
forming part of the peeler and laminator apparatus;
FIG. 2 is a schematic view of an adjustable peeler or delaminating
apparatus of the present invention depicted in one mode of
operation;
FIG. 3 is a schematic view of the peeler apparatus of FIG. 2, but
with the components thereof depicted in another mode of
operation;
FIG. 4 is a schematic view of the peeler apparatus depicted with
the components thereof in still another mode of operation;
FIG. 5 is an enlarged schematic view of a nested pair of peeler
bars in one mode of operation corresponding to FIG. 4;
FIG. 6 is an enlarged schematic view of a nested pair peeling bars
in another mode of operation;
FIG. 7 is an enlarged and fragmented perspective view of some of
the components of the peeling assembly of the present
invention;
FIG. 7A is a side elevational view of one of the traction ring
elements;
FIG. 8 is a side elevational view of FIG. 7;
FIG. 9 is a partial plan schematic view of the operative components
viewed in FIG. 8;
FIG. 10 is a partial view of the drive components of the peeler
assembly;
FIG. 11 is a partial view of other drive components of the peeler
assembly;
FIG. 12 is a fragmented perspective view of a sheet of dry imaging
laminate; and,
FIG. 13 is a cross-sectional view of the media which can be peeled
in accordance with the present invention.
DETAILED DESCRIPTION
Referring to the drawings and, in particular, to FIG. 1, there is
shown a peeler and laminator apparatus 20 in which a peeler or
delaminator apparatus 22 of the present invention is incorporated.
The peeler apparatus 22 is operative for peeling thin laminated
sheets of dry peel-apart imaging media and then laminating at least
one of the peeled layers of the imaging sheet. Features of a peeler
and laminator apparatus 20 which are necessary for understanding
the operation of the peeler or delaminator apparatus 22 of the
present invention will be described.
Essentially, the peeler and laminator apparatus 20 includes a sheet
feeding station 24, a sheet tabbing station 26, a sheet peeling
station 28 at which the peeler apparatus 22 is located, a
laminating station 30, and a laminated sheet exiting station 32.
The peeler apparatus 22 of this invention is versatile and is
operative for peeling a variety of sheets of dry laminar imaging
media, such as thermographic or photopolymerizable types of media.
For example, the type of thermographic imaging material which can
be used can be used is like that described in commonly assigned
International Application PCT/03249/US87 published Jun. 16, 1988,
under International Publication No. W088/04237.
Insofar as other peel-apart dry laminar imaging media are
concerned, reference is made to a photopolymerizable material which
is depicted in FIGS. 12 and 13. The depicted photopolymerizable
laminar imaging sheet medium 34 provides a pair of complementary
images (one of which is a duplicate image of an original) and the
sheets of which can be separated using the peeling apparatus of the
present invention. Such a sheet medium 34 provides a pair of high
resolution images and includes a first sheet 36 having superimposed
thereon a multicomponent layer 38 which includes in order, a
photopolymerizable layer, an image-forming layer comprising a
photopolymerizable material (which may be the same as, or different
from, the photopolymerizable material present in the
photopolymerizable layer) and a dye or pigment, a release layer, an
adhesive layer; and, a second or releasable throwaway layer or
sheet 40.
One type of imaging medium is imagewise exposed to radiation
(typically, near ultra-violet radiation) of a wavelength effective
to cause polymerization of the photopolymerizable material(s)
present in the photopolymerizable and image-forming layers, this
exposure usually being effected through the first sheet. In exposed
areas such as 38a, the imaging radiation causes polymerization of
the photopolymerizable material(s) present in the
photopolymerizable and image-forming layers, and thus increases the
adhesion between the exposed portions of the photopolymerizable and
image-forming layers, and the first sheet 36. Accordingly, when the
first ("keeper") and second ("throwaway") sheets are separated
after the imagewise exposure, in exposed areas 38a the
photopolymerizable and image-forming layers remain attached to the
first sheet and cohesive failure occurs within the release layer to
provide an image which is the reverse (i.e., a wrong-reading image)
of the original image through which the exposure is made. In
unexposed areas such as 38b, the image-forming layer remains
attached to the second sheet 40, and cohesive failure occurs within
the photopolymerizable layer, to provide a duplicate ("dupe") of
the original.
In contrast to the aforementioned imaging medium, a laminar imaging
medium which provides a "keeper" image in the form of a negative
"contact" image of the original image.
A principal embodiment of such a laminar medium comprises a
photoplasticizable layer comprising a macromolecular binder and an
onium salt, these components configured such that the layer becomes
at least partially plasticized upon exposure to actinic radiation;
a layer of a porous or particulate imaging material adjacent to the
photoplasticizable layer; a first sheet (cf., cover sheet) secured
to the photoplasticizable layer; and a second sheet (cf., support
or "keeper" sheet) adhered to the face of the imaging material
remote from the photoplasticizable layer. In general, the onium
salts selected for such configuration are those capable of
generating a plasticizing species in response to irradiation with
actinic radiation. After exposure to actinic radiation, the
plasticizing species generated from the onium salts plasticizes the
macromolecular binder, effectively tackifying the
photoplasticizable layer in areas of exposure, these tackified
areas presenting areas of reduced interfacial adhesivity between
the photoplasticizable layer and the cover sheet. When the cover
sheet is separated (i.e., peeled) from the support sheet,
irradiated areas are retained on the support sheet to provide a
"contact" image, while non-exposed areas are carried away on the
cover sheet. In view of its distinct configuration, it will be
appreciated that the peel forces desirable for effecting preferred
separation conditions for the development of this imaging medium
vary from those desirable for the development of the aforementioned
laminar imaging medium. Regardless, as made apparent herein, the
delaminator of the present invention is well-suited for effecting
delamination of either of the noted photopolymerizable medium.
Individual ones of the sheets 34 of the imaging media are manually
fed to a pair of in-feed nip rollers 42 and 44 of the sheet feeding
station 24. The rollers 42 and 44 are operative for advancing
imaging sheets to a tabber apparatus 46 located at the tabbing
station 26. The sheet feeding station and the tabbing station
including the tabber apparatus are like that described in the noted
commonly assigned and copending patent application entitled "MEDIA
TABBING APPARATUS AND METHOD"; and, a description thereof are
incorporated herein by reference. In this embodiment, a plurality
of sheets of various sizes can be fed in side-by-side relationship
to the tabber apparatus. The tabber apparatus 46 is operative for
forming a frangible tab 50 (FIGS. 3 & 12) on a leading edge of
each individual sheet 34. The tab 50 is used for initiating
delamination of throwaway sheet from the keeper sheet as will be
described. The tabber apparatus 46 forms the frangible tab 50 by a
transversely reciprocatable shuttle block means assembly 52
carrying a tabbing cutter 54 for scoring the keeper sheet along the
latter's forward edge. With the completion of the tabbing, the
shuttle block assembly 52 is disposed at either lateral extremity
of the sheet feeding path. A chute means or assembly 56 is operated
to pivot to the position, depicted in FIG. 1A, whereby the scored
frangible tab 50 and associated sheet can enter as it is driven by
the peel in-feed nip rollers 42, 44. The chute assembly 56 guides
the sheet 34 downwardly to a sheet transporting system 58. The
sheet transporting system 58 includes a series of 0-ring conveyor
belts 59 (FIG. 1a) which extend transversely between the sideplates
of the frame and are driven by a suitable drive system. The sheet
transporting mechanism 58 operates to feed the sheets through a
pair of arcuately shaped, spaced apart, guide plates 60 which are
situated adjacent the entrance to the peeler apparatus 22. The
plates 60 extend between the frame sideplates so as to guide a
plurality of discrete sheets to the peeler apparatus.
As will be explained, the peeler apparatus 22 is effective for
separating the throwaway sheet 40 from the keeper sheet 38 without
inducing unacceptable image artifacts in the image on the keeper
sheet. The peeling apparatus 22 of this embodiment includes a sheet
tensioning assembly 62; a peeling bar assembly 64; peel tractor
roller means 68; a keeper deflector roll assembly 70; and, a waste
conveyor system 72.
Initial reference is made to FIGS. 2-4 and 7 & 8 for depicting
the sheet tensioning assembly 62. In this embodiment, the sheet
tensioning assembly 62 is segmented and includes a plurality of
axially spaced apart elastomeric peel tension rollers 74; each
having a generally tubular shape. Each of the peel tension rollers
74 is rotatably mounted on an elongate and stationary mounting axle
76 which, in turn, is mounted to extend transversely to the
direction of sheet feeding. The mounting axle 76 is relatively
flexible and such flexibility enables the rollers 74 to follow the
contours of the peel bar. The mounting axle 76 is mounted within a
curled portion 78 at a distal end of each of a plurality of axially
spaced apart wire springs 80a, one of which is depicted in FIG. 7.
Each of the wire springs has a proximal end pivotally attached to
an axle 84 that is mounted on the underside of a sheet guide plate
86. The guide plate 86 is connected to and between the peel frame
sideplates 88 (FIG. 9). The use of wire springs allows each of the
rollers 74 to abut each other. In this regard, an axial adjusting
nut or the like (not shown) forces the rollers 74 into lateral
abutting relationship with each other.
There is provided a pair of axially spaced apart and depending
actuator posts 90 (only one is shown) which have one end of a pair
of springs 92 attached to them, while the other spring ends are
fixedly attached to each frame sideplate. The springs 92 are
arranged to normally bias the actuator posts 90 and thereby the
tension rollers 74 to their sheet engaging position; see the solid
line position thereof in FIGS. 2, 4, and 8, whereby tension is
provided on any sheet being squeezed thereby. The tension rollers
74 are moved to their inoperative position by having the biasing
force of the springs 92 overcome by the peel tractor roller means.
In particular, the peel tractor roller means 68 is operative to
engage and pivot the sheet tensioning assembly through the lever
158 and, therefore, its associated tension rollers 74 to their
inoperative or non-engaging position, see FIG. 3 as when the peel
tractor roller means moves to its pre-peel position. The springs 92
drive the tension rollers 74 to their sheet engaging position when
the peel tractor means moves to its peeling position. Referring
back to the tension rollers 74, each is self-adjusting for applying
uniform pressure against the bottom of the imaging sheets. In this
regard, the rollers 74 are made, preferably, of a resilient
polyurethane foam material which is sufficiently flexibly resilient
for acting as a spring which pinches the sheets. Because the
rollers 74 are segmented they provide a consistent force regardless
of sheet width. The segmentation provided by the individual rollers
74 insures that tension is applied against the sheet. Because the
tension rollers 74 are independently rotatable in order to
facilitate continued sheet feeding of multiple sheets of varying
widths, at the same time, they can feed the sheets without the need
for special instrumentation sensors and the like for measuring
sheet dimensions and controlling related sheet feeding and peeling
activities. The rollers 74 which are made of a resilient material
have the frictional and compressive properties for effecting such
spring-like qualities. In addition, they perform the peeling
without damaging the film sheet surface. Some of the other
materials contemplated by this invention for use in the
construction of the rollers include: natural and synthetic rubbers.
These materials are illustrative and not limiting.
Referring now to FIGS. 2-4, 7 and 8, the peeling bar assembly 64,
includes a main peel bar 94 and an auxiliary peel bar assembly 96,
either of which is operative for effecting peeling as will be
described. In this embodiment, the main peel bar 94 is defined as
an elongate member having locator pins 98 at opposite axial ends
thereof which fit within respective openings (not shown) within the
peeler frame sideplates 88. In this manner, the main peel bar 96
extends transversely to the feeding path of the imaging sheet 34.
The main peel bar 96 has a relatively enlarged and arcuate peel
tractor peeling surface 100 which has a configuration that conforms
to a portion of the periphery of the peel tractor elements. The
peeling surface 100 is generally arcuate, smooth and has a
relatively low coefficient of friction so as to enhance peeling.
The peeling surface 100 may be coated with a suitable low
coefficient of friction material; such as zirconia/Teflon plasma
coatings, such coatings are illustrative and not limiting.
Reference is made to FIGS. 2-6 for better illustrating that the
main peel bar 94 is provided with a curved peeling edge 104 which
has a profile that has been determined to effect desired peeling of
the "dupe" film sheet material. In this embodiment, the peeling
edge 104 has a radius of curvature in a range from about 0.015 to
0.062 inch. In one preferred embodiment, the radius of curvature is
0.032 inch. An upper portion of the peeling surface 100 terminates
at a location 102 relative to the waste conveyor system 72, such
that as the leading edge of a throwaway sheet leaves the peel
surface, it travels between an elongate and transversely extending
lower waste guide member 106, and the lower flights of a series of
axially extending 0-ring type conveying belts 108. The operation of
the waste conveyor system 72 in removing the throwaway sheet does
not, per se, form a part of the present invention.
If it is desired to peel "contact" sheet material, the auxiliary
peel bar assembly 96 is moved from its inoperative position, as
shown by dotted lines in FIGS. 2-4, to its operative position as
depicted by solid lines in FIGS. 2-4. In the illustrated
embodiment, the auxiliary peel bar assembly 96 includes a generally
elongated auxiliary peel bar 110 having a generally U-shaped
cross-section which defines a.sub.-- longitudinally extending
central cavity 112 that has a sliding relationship with the main
peel bar 94. For the sake of compactness, an air cylinder 114 is
mounted to peel bar 110. For the sake of compactness it is mounted
along a longitudinal axis of the auxiliary peel bar 110. Actuation
of the air cylinder 114 extends its piston rod along the axis of
the auxiliary peel bar 110. Because of a cam follower 116 which is
attached to the piston rod and which is riding in an angled cam
slot 118 and a similar arrangement (not shown) on the other end,
such motion is converted into corresponding sliding motion of the
auxiliary peeling bar 110 in the direction which is generally
parallel to the sheet feeding path. The auxiliary peel bar 110
moves to the operative position as shown by the solid lines in
FIGS. 2-6 and is stopped there when mating peel bar surfaces 94a,
110a (FIG. 8) contact. Retraction of the piston rod will move the
auxiliary peel bar 110 to the non-operative position shown in
phantom lines in FIGS. 2-4.
In this embodiment, the auxiliary peel bar 110 has an elongated
peeling edge 120 which has a peeling profile as illustrated that
has been determined to be effective in peeling of the "contact"
film sheet material. In this regard, the curved peeling edge 120
has a preselected radius of curvature; which radii can in this
embodiment range from about 0.015 to 0.250 inch. In a preferred
embodiment, the radius is 0.062 inch. Other radii of curvature are
contemplated depending on the type of material being peeled. It
will be appreciated that whatever the peeling characteristics of
the material being peeled are, the peeling edge profile should be
selected so as to effect the desired peeling. As illustrated when
the auxiliary peel bar 110 is in its operative position as seen in
FIGS. 3-5, both the peeling edges 104 and 120 are generally
vertically aligned so that the peeling edge 104 does not interfere
with the operation of the peeling edge 120 of the auxiliary peeling
bar 110. While this embodiment depicts a nested arrangement of the
peeling bars, it will be appreciated that the present invention
contemplates other constructions wherein different peeling edge
configurations can be placed in operative relationship for
effecting the peeling of laminated sheets having different peeling
characteristics.
Reference is now made to the peeling tractor means or mechanism 68
which includes a peel tractor roll assembly 122, and a peel tractor
roll drive assembly 124. The tractor roll assembly 122 comprises a
plurality of axially spaced apart tractor tires or ring elements
126 which are mounted on a peel traction drive shaft 128. The
tractor rings 126 are effective for engaging the tab and throwaway
sheet as will be described. In this embodiment, the tractor rings
126 are about 1/4 inch wide and are spaced apart by about 1 inch.
Other tire dimensions and spacings are contemplated. The tractor
rings 126 are, preferably, flat faced and made of polyurethane.
As seen in FIG. 7A, the tractor rings 126 have a plurality of voids
130 having a size and configuration, such as the type shown in the
drawings, formed therein which enhance radial compressibility of
the ring and hence, conformity of the tractor rings to the peel
bar. However, the voids 130 are formed so as to avoid diminishing
the torsional stiffness of the ring 126. In this embodiment, the
rings 126 are made of a compressible polyurethane having durometers
of for example, 75-85 Shore A, but can be made of other suitable
materials having other hardness. Polyurethane is preferred, because
it has a relatively high coefficient of friction and desirable
torsional stiffness and abrasion resistance. As a result,
polyurethane provides the necessary sheet friction drive and,
importantly, does not damage the surface of the sheets being
peeled. Other materials which can accomplish the above advantages
can, of course, be used, such as comparable natural or synthetic
rubbers.
As will be described, as the peel tractor drive shaft 128 is driven
upwardly in a circular arc from its pre-peel position (FIG. 2)
below the peel bar assemblies to its peeling position (FIG. 4-6),
it breaks the frangible tab 50 and bends the latter onto the peel
surface 100. As the peel tractor shaft 128 rotates about its own
longitudinal axis, it commences peeling of the throwaway sheet
between the tractor rings 126 and the peeling traction surface 100.
It will be noted that the peeling is performed by the tractor rings
126 driving the throwaway sheet in the direction of the arrows. The
rotational speed of the shaft 128 can be adjusted to whatever
speeds are desirable for peeling a particular medium. Because of
the natural arc swing of the peel tractor roll assembly 126, the
frangible tab and the leading edge of the throwaway sheet 40 are
wrapped tightly onto one or both of the noted peeling edges 104 and
120; depending on whether the contact or dupe material is being
delaminated. This arc swing has been determined to avoid the
formation of a space or gap between the sheet 34 and the peeling
edges. Presence of such a space has been determined to have a
tendency which results in the formation of image artifacts being
present in the final product. The peeling action results in the
throwaway sheet 40 being peeled by the peel tractor roll, while the
keeper sheet advances towards a laminating station, whereat the
surface thereof is protected with a laminating coating.
The lamination step does not form part of the present
invention.
Reference is now made to FIGS. 9-11 which better illustrate the
tractor roller drive assembly 124. One end of the peel tractor
shaft 128 has a pinion gear 132 attached thereto for meshing
cooperation with the internal circumferential teeth of a ring-gear
134. The ring-gear 134 is mounted for rotation on a sidewall 88 of
the peeler and is directly coupled to a coaxially arranged input
pulley 136 which is driven through a drive belt by a source of
rotational power, such as d.c. motor 138. Hence, rotation of the
input pulley 136 drives the ring-gear 134 which, in turn, rotates
the peel tractor roller drive shaft 128. As noted, the rotational
speed of the peel tractor rings 126 is selected to achieve the
desired continuous peeling action. The speed will depend on the
type of material being peeled. As described more fully in the last
noted application, the d.c. motor 138 also drives the waste
conveyor or stacker system 72.
For effecting the noted up and down swinging action of the peel
tractor drive shaft 128 between the pre-peel position and the
peeling position, the latter is mounted in a bearing (not shown)
carried in a bore 139 of a crankplate 140 only one of a pair is
depicted.
The crankplate 140 is mounted for oscillatory movement on one side
of the peeler frame assembly, while the other crankplate 140 is
mounted for similar movement on the opposite side of the peeler
frame assembly. The crankplate 140 has a segmented plurality of
teeth 142 along one arcuate edge thereof which meshes with teeth of
one of a pair of drive pinion gears 144 that is mounted to a common
shaft rotatably driven by a d.c. motor 146 which can be operated so
as to either raise or lower the crankplate and, therefore, the peel
tractor roll drive shaft 128. The common shaft is connected to and
between the sideplates.
As a result, the peel tractor roll assembly 122 is cranked from the
pre-peel position, as shown in FIG. 3 to the peeling position as
shown in FIG. 4 in a natural swinging or rotating action. During
this generally circular motion, the tractor tires 126 engage the
tab 50, FIG. 3, and urge the throwaway sheet 40 to its folded over
position relative to one of the peel edges.
For this to happen, each of the peeler sideframes has an arcuate
slot 147, only one is illustrated, which allows the peel tractor
shaft to move in a generally circular path in order to effect the
foregoing swinging displacement. Also, the tab 50 is fed to a
controlled position located adjacent the edge of one of the peeling
bars (FIG. 3). The position of the sheet 34 is controlled by
position sensors, not shown, and the operation of the in-feed
rollers of the in-feed mechanism 58. Specifically, the position of
the sheet is such that a hinge of the tab 50 is located in
juxtaposed relationship to at least one of the peel edges so that
the tab can be folded in relative tight engagement thereover in a
manner which avoids the formation of bags. As the peel tractor
roller drive shaft moves to the peeling position, the tires 126
bend the tab over the peel edge and into intimate engagement with
the peel slip surface 100. This acts to minimize the formation of a
bag or space existing between the throwaway sheet and the peel
edge. The peel traction roll shaft 128 is driven by the ring-gear
and pinion gear arrangement at a predetermined speed. The speed is
selected to effect the desired peeling of the medium in a manner
which does not form image artifacts. For peeling the noted contact
and dupe material, the rotational speeds of the shaft 128 can be
varied. In this embodiment the speeds can range in the order of
about 1-12 inches per second. However, other speeds can be used
depending on the type of material being peeled. In this embodiment,
the pinion gear and the ring-gear have a constant center distance
therebetween and thus remain in perfect engagement as the peel
tractor roll is swung in its circular path. Otherwise complicated
mechanisms would have to take into account the fact that there is a
swinging rotational axis for the peel roller.
As noted, the keeper sheet 36 is delaminated from the throwaway
sheet 40. Reference is made to FIGS. 3-6 for illustrated how the
keeper sheet 36 is deflected by the adjustable keeper deflector
assembly 70. Deflection of the keeper sheet 36 is one of the
peeling parameters for controlling the nature of peeling. In this
regard, the deflection angle A of the keeper sheet 40 is selected
so as to effect the desired peeling without appreciable defects.
The adjustable keeper deflector assembly 70 includes an elongate
deflecting roller 148 which is rotatably mounted on a shaft 149 and
extends transversely to the sheet feeding path. The roller 148 is
made of polished steel with a release coating which does not damage
any of the sheet medium in engagement therewith. Other suitable
materials can also be used. The deflecting roller 148 is in
engagement with the traction tires when they are in their operative
positions and freely rotates in response to the rotational motion
of the traction tires 126. Each axial end of the shaft 149 extends
through a slot 150 and is retained for rotation therein and for
limited axial movement in a distal end of a pivotal arm retainer
member 152. The retainer arms 152 are pivotally attached to the
peeler frame sideplate 88 and are biased upwardly by a spring 154
so that the deflector assembly can follow the movement of the
traction roller as described. For adjusting the deflection angle,
there is provided a motive power source, such as an air cylinder
156 which is coupled to one end to the shaft 149, such that
extensions and retractions of an air cylinder piston causes
corresponding linear movement of the deflector roller shaft 149 and
hence the deflector roller 148 into one of two distinct positions.
These two positions of the roller 148 relative to the pivot axis of
the retainer arm 152 provide for two distinct deflection angles of
the keeper sheet 36. Each of the selected respective deflection
angles enhances peeling of a contact medium and a dupe medium.
Other mechanisms are contemplated for controlling the position of
the deflector roller 148. For peeling the dupe sheet, the
deflection angle A of the keeper sheet 40 leaving the peel nip,
such as viewed in FIG. 6 can be in a range of about 0.degree. to
20.degree.. For peeling the contact sheet, the deflection angle can
be in a range of about 0.degree. to 20.degree..
Since the adjustable deflection roller assembly 70 is passive it
will follow the noted movement of the peel tractor roll assembly.
The deflecting roller 148 engages the tractor ring elements 126 and
is driven thereby, whereby both the deflecting roller and the
tractor rings rotate at the same speeds and therefore do not impart
any scuff marks to the keeper sheet 40. The keeper deflector roller
148 moves from its operative position (see the solid lines in FIG.
2) to its inoperative position (see the phantom lines in FIG. 2)
when the peel tractor roll assembly 122 moves from its peeling
position (see solid lines of FIG. 2) to its pre-peel position (see
phantom lines in FIG. 2). It will be noted that the deflector
roller 148 is spaced from the tractor rings 126 when both are in
their inoperative positions so as to avoid flats forming on
mutually engaging peripheral surfaces of the rollers.
Also, the tensioning rollers 74 are spaced from the tractor tires
126 when both are in their inoperative modes. In this regard, a
lever 158 (FIG. 7) is mounted on the tensioning assembly for
movement therewith. The lever 158 has one arm 160 the lower edge of
which engages a portion of the deflector shaft 149 and the upper
side of which engages the peel roller shaft 128. As the lever 158
rotates about 84 it is pushed by the peel roller shaft downwardly
to the pre-peel position, its arm 160 continues to move and force
the deflector roller assembly and the tension roller assembly;
respectively, from the peel traction tires 126. Although downward
deflection is shown and described, it will be appreciated that the
present invention envisions upward deflection of the keeper
sheet.
After having explained the construction of the peeler apparatus of
the present invention, its operation is believed to be
self-evident. However, to supplement that description the following
sets forth the basic operation of the peeler apparatus. The peel
tractor means 68 is actuated to swing upwardly from a pre-peel
position (FIG. 2) below and out of the way of an advancing tabbed
sheet 34 to the peel position (FIG. 3). In this regard, the
crankplate 140 is pivoted upwardly and the peel tractor rings 126
engage and fold the tab 50 upwardly and tightly wraps it about a
peeling edge. The tab is folded by the natural circular movement of
the peel tractor means. The tab 50 and the waste sheet 38 are
adapted to ride upon the low friction arcuate peeling surface 100
of the main peeling bar 94 as the rings 126 rotate at a preselected
speed. The speed has been determined to effect the desired peeling
of which ever medium is being peeled. When the tractor roll
assembly 122 is in its peel position, the throwaway sheet 38 is
pinched and positively advanced by the compliant material of the
rotating traction rings 126. There is no need for a pair of peel
rollers during peeling of the strip sheet since the single peel
traction roller assembly 122 is effective to produce peeling.
During the upward movement of the peel traction roller assembly 122
both the passive sheet tensioning assembly 62 and the adjustable
keeper deflector roller assembly 70 move from their non-operative
positions to their operative positions as indicated in FIGS. 2 and
4-6. As noted, both of the latter two assemblies are spring biased
into such positions in response to displacement of the peel
traction roller assembly 122 from its pre-peel position to the peel
position.
In regard to the tensioning rollers 74, it will be appreciated that
since they are passive, they will move under the biasing of the
spring 92 and follow the peel traction roller as the latter moves
to its sheet driving position. In doing so the tensioning rollers
will engage and squeeze the sheet (FIG. 4). The tensioning rollers
are allowed to rotate with the passing sheet which is being
squeezed thereby.
As shown in FIG. 5, the peel traction roller means 68 is moved with
the traction tires 126 forced against a throwaway sheet 40. The
tensioning rollers 74 are moved to a position in contact with the
sheet medium 34, and the deflector roll 148 is moved to a position
to deflect the keeper sheet and feed the keeper sheet 40 outwardly
from the peeler delaminator 22. The deflector roller 148 is
simultaneously positioned beyond the peel point and is brought into
contact with the traction peeler means 68 so as to be driven
thereby and thus avoid imparting any scuff marks on the keeper
sheet 40. As noted, the deflector roller 148 is adjustable so as to
deflect the keeper sheet 36 by a controlled angular deflection. The
angular deflections vary based on the type of material being
peeled, for example, whether contact or dupe material is being
processed so as to insure that the peeling is done in a manner
which minimizes introduction of image artifacts in the resulting
keeper sheet. For adjusting whether the deflecting roller 148 is
positioned in either of its two positions, the air cylinder 156, as
noted, changes the radius of curvature of the deflector retainer
arm 152 relative to the pivot axis of the latter.
If, on the other hand, it is desired to peel dupe material, then
the auxiliary peel bar is moved into its operative position under
the control of the air cylinder 114; as seen in FIG. 7. As a
result, the peeling apparatus can peel the dupe material as it has
peeled the contact material.
Although several specific and preferred methods and apparatus of
the present invention have been shown and described above, other
variations of the present invention will become apparent to those
skilled in the art. The scope of the invention is therefore not
limited to the specific forms shown and described but rather is
indicated by the claims below.
* * * * *